Broadside Compensation Rolling Model for Plan View Pattern Control in Wide and Heavy Plate Rolling Process

On the basis of a 5 m plate mill, a 3D rigid-plastic finite element （FE） model was developed to investigate changes of plate plan view patterns during hot rolling process. By analyzing the simulation results of conventional rolling processes, it was found that the plate plan view pattern was closely related to broadside rolling ratio. Then, the prediction models for plate plan view patterns were formulated by nonlinear regressive analysis of the simulation results and modified for high accuracy. Based on these models, the broadside compensation rolling method perform- ing at the last pass of broadside rolling phase was designed to decrease plate end crops. Comparing the plate plan view patterns with and without broadside compensation roiling, reduced plate end crops indicate that the broadside compensation roiling model is effective for plate plan view pattern control.

Review of the last three years since the commissioning of Baosteel's 5m heavy plate plant and future outlook

Baosteel＇ s 5m heavy plate plant was successfully tested on March 1,2005. Since then,the Heavy Plate Plant of Baosteel （hereinafter referred to as ＂the plant＂ ） has been encouraging its employees to study and trace the advanced heavy plate technologies, trying to find out the rules of heavy plate production and its quality control. The plant has gradually mastered this modem heavy plate plant and ensured that Baosteel＇ s production of heavy plates grew year by year,with 1.41 Mt product put in storage in 2007. The plant has focused on developing new technologies and products, meanwhile enhancing its capacity. It has produced a series of plate products, which can be used in manufacturing ship hulls ,pipelines ,bridges ,buildings ,boilers and pressure vessels.

Numerical simulation research of dimension variation in heavy plate during quenching and tempering process

The dimension variation of B610E steel during the quenching and tempering process was simulated by ABAQUS,the coefficient of heat transfer during quenching was verified by the buried thermocouple test and the trend of the dimension variation during the quenching process was also calculated by ABAQUS. It was shown by the comparison of simulated results and industrially measured results that only the simulation of thickness and width variation was accurate, while length variation needed further simulation. Besides, the dimension variation trend was identical with the measured results.

Experimental study on the moving characteristics of fine grains in wide grading unconsolidated soil under heavy rainfall

The initiation mechanism of debris flow is regarded as the key step in understanding the debrisflow processes of occurrence, development and damage. Moreover, migration, accumulation and blocking effects of fine particles in soil will lead to soil failure and then develop into debris flow. Based on this hypothesis and considering the three factors of slope gradient, rainfall duration and rainfall intensity, 16 flume experiments were designed using the method of orthogonal design and completed in a laboratory. Particle composition changes in slope toe, volumetric water content, fine particle movement characteristics and soil failure mechanism were analyzed and understood as follows: the soil has complex, random and unstable structures, which causes remarkable pore characteristics of poor connectivity, non-uniformity and easy variation. The major factors that influence fine particle migration are rainfall intensity and slope. Rainfall intensity dominates particle movement, whereby high intensity rainfall induces a large number of mass movement and sharp fluctuation, causing more fine particles to accumulate at the steep slope toe. The slope toe plays an important role in water collection and fine particleaccumulation. Both fine particle migration and coarse particle movement appears similar fluctuation. Fine particle migration is interrupted in unconnected pores, causing pore blockage and fine particle accumulation, which then leads to the formation of a weak layer and further soil failure or collapses. Fine particle movement also causes debris flow formation in two ways: movement on the soil surface and migration inside the soil. The results verify the hypothesis that the function of fine particle migration in soil failure process is conducive for further understanding the formation mechanism of soil failure and debris flow initiation.

Effect of gradient temperature rolling process on promoting crack healing in Q500 heavy plates

To ensure the quality of heavy plate products as determined by ultrasonic inspection, it is necessary to effectively control defects such as cracks and shrinkage cavities in heavy plates. Generally, some defects such as large size cracks exist due to insufficient deformation in the center of traditionally rolled plates. Compared with the traditional rolling process, gradient temperature rolling(GTR) process can effectively increase deformation inside heavy plates. In this study, the effect of GTR on crack healing was analyzed through a comparison experiment with the uniform temperature rolling(UTR). The results show that the GTR process could increase the plastic strain inside the heavy plate and effectively promote the healing process of the preset cracks. The degrees of crack healing at the center and quarter thickness position of the steel plate via GTR were greater than twice those of the plate via UTR. The GTR process can significantly reduce the internal defects of heavy plates and improve the defect detection level of heavy plate products. Also, The GTR process results in the formation of new crystal grains in the crack region, which is crucial to crack healing.

FEM study on inflow strain in heavy plate during rolling

Heavy plate rolling processing in every single pass was simulated by the method of FEM. Distribution of the inflow strain on the specified path and related parameters （plate thickness H, pass reduction dH, rolling speed V） in the thickness direction of the plate center were studied. The results show that the plate thickness H and pass reduction dH have significant effects on the inflow strain on the specified path, while the rolling speed presents little effect. The relationships between the strain （PEEQ） and the plate thickness （H）/pass reduction （dH） were also established based on the simulation results.

Industrial practice of clad-rolling in heavy steel plate production

In this paper,a brief introduction on clad-rolling heavy steel plates of 90 mm and 140 mm thick is presented.The steel plates were hot rolled by 265mm slabs that are cladded by double 135mm continuous casting slabs of Q235 steel.After hot rolling,interface of the cladding slabs completely disappeared, revealing uniform grains similar to the rest of the materials.Ultrasonic tests were carried out on both steel plates,demonstrating excellent results.Through thickness tensile tests were also implemented on both steel plates,resulting in perfect mechanical properties complying with specific standards.The result proves that a minimum reduction rate of 1.89 is available in producing 140 mm thick steel plate with excellent through thickness properties.

Advances in nuclear detection and readout techniques

“A Craftsman Must Sharpen His Tools to Do His Job,”said Confucius.Nuclear detection and readout techniques are the foundation of particle physics,nuclear physics,and particle astrophysics to reveal the nature of the universe.Also,they are being increasingly used in other disciplines like nuclear power generation,life sciences,environmental sciences,medical sciences,etc.The article reviews the short history,recent development,and trend of nuclear detection and readout techniques,covering Semiconductor Detector,Gaseous Detector,Scintillation Detector,Cherenkov Detector,Transition Radiation Detector,and Readout Techniques.By explaining the principle and using examples,we hope to help the interested reader underst and this research field and bring exciting information to the community.

Study on the rolling process for thin HSLA heavy plates

Analyzed and studied the characters of high strength low alloy steel which contain Mo,Cr,Nb and Ni.etc.Following actual rolling,combining the feature of rolling mode,and exploiting the equipment advantage of 5 m Heavy Plate Mill,optimized the material design,heating temperature and rolling method, stabilized rolling process of thin alloyed steel,the quality index was advanced.

Tapered heavy reduction technology for plate mill

This paper describes the benefits, technical difficulties and disadvantages of the current heavy reduction solutions for plate production. For updated plate mills,this paper gives a better idea for the heavy reduction control in the rolling process. That is to keep the reduction amount constant in the front-end and back-end sections of the plate and to adopt tapered rolling with variable reduction in the middle section of the plate. This solution （ already applied for a patent） can not only fully utilize the capacity of the mill motors, but also prevent difficulties in plate biting caused by the conventional heavy reduction solutions with excessive draft. This technical solution has been implemented at the 5 m plate mill plant of Baosteel,and industrial tests have proved the feasibility of it. This paper presents and analyzes the industrial test data and proves that the tapered heavy reduction technology can reduce the number of rolling passes. In addition ,this paper looks forward to the future research in this area.

Development of high strength heavy plate A517Q for offshore platform rack

This paper introduces the research and development of high strength A517Q developed by Baosteel for platform rack,with micro-alloying adding suitable quenching and tempering process,trial thickness of 127 - 178 mm high-strength A517Q.The trial plate crossing thickness has a uniform mechanical properties, yield strength greater than 700 MPa,tensile strength than 790 MPa,the Charpy impact than 90 J at -40℃, aging impact than 69 J,has high strength and excellent low temperature impact toughness,While the plate has excellent resistance to crack tearing ability of low-temperature,NDT is less than -45℃.The Developing heavy plates had been used for manufacturing racks of 200-foot jack-up offshore platform,the performance meeting the requirements of the ABS,CCS classification societies.

Design of scale model of plate-shaped absorber in a wide frequency range

In order to design the scale model in a wide frequency range,a method based on the reflective loss is proposed according to the high-frequency approximation algorithm,and an example of designing the scale model of a plate-shaped absorber is given in this paper.In the example,the frequency of the full-size measurement ranges from 2.0 GHz to 2.4 GHz,the thickness of the full-size absorber is 1 mm and the scale ratio is 1/5.A two-layer scale absorber is obtained by the proposed method.The thickness values of the bottom and top layer are 0.4 mm and 0.5 mm,respectively.Furthermore,the scattering properties of a plate model and an SLICY model are studied by FEKO to verify the effectiveness of the designed scale absorber.Compared with the corresponding values from the theoretical scale model,the average values of the absolute deviations in 10 GHz～12 GHz are 0.53 d Bm^2,0.65 d Bm^2,0.76 d Bm^2 for the plate model and 0.20 d Bm^2,0.95 d Bm^2,0.77 d Bm^2 for the SLICY model while the incident angles are 0°,30°,and 60°,respectively.These deviations fall within the Radar cross section（RCS） measurement tolerance.Thus,the work in this paper has important theoretical and practical significance.

管道环焊缝拉伸应变容量模型分析及改进

为了确保石油天然气管线在复杂服役环境下的本质安全,探讨了目前国内外广泛应用的3种管道环焊缝拉伸应变容量模型(CSA Z662、PRCI-CRES、EXXON MOBIL),并对其参数选取范围性进行了汇总和对比分析。通过分析模型预测值和96组全尺寸管道及宽板拉伸试验数据的差异,对各拉伸应变容量模型在不同钢级下的预测精度进行了验证,并使用90%置信上限倒数法计算了模型安全系数。结果表明:由于CSA Z662模型断裂韧性取值上限过小,导致其对于中、高钢级管线的预测值过于保守;EXXON MOBIL和PRCI-CRES模型更为完善,二者预测结果相似,并与试验结果较为相符。针对EXXON MOBIL和PRCI-CRES模型计算所得的安全系数可以明显改善模型预测结果,可将非保守预测值最大误差控制在约30%范围内,从而有效满足较为保守的设计要求。研究结果可为管线基于应变设计提供理论指导。

厚板轧制过程轧件翘扣头控制的有限元研究

利用ABAQUS有限元软件,模拟了厚板的轧制过程,计算了一系列可调控的工艺参数对轧件翘扣头的影响。可调控的工艺参数主要包括轧制中心线位置H i、上下轧辊的辊速差S k i和轧件上下表面温度差ΔT。计算结果表明,通过调整H_(i)、S_(ki)和ΔT,可以分别在2 m长度轧件上获得-17.5 mm、-181.0 mm和-200.0 mm的翘扣头控制量。进一步的分析表明,调节上下辊的辊速差、轧件上下表面温度差可较为有效地控制轧件翘扣头,且上下表面温度差对轧件翘扣头的控制能力更强。

特厚板连铸七辊大压下扇形段辊缝控制模型

针对某特厚板连铸的七辊大压下扇形段,根据其结构特点及机架上框架、扇形段内外弧辊与夹紧油缸之间的关系,并通过数学公式推导,建立了辊缝调整的控制模型。该模型通过控制大压下扇形段的每个夹紧缸的位移量,实现扇形段入口、出口辊缝值的精确控制。利用该模型对三种不同工况的铸坯进行重压下实验,按照预先设定好的压下量及压下速率精确控制每个扇形段的动作过程,结果表明,铸坯中心疏松及缩孔明显减少,大大改善了铸坯质量。

矿用重载轮胎趾口空问题的研究

通过市场返回轮胎断面剖析,结合有限元仿真分析造成矿用重载轮胎趾口空的原因,并提出相应的解决措施。通过采取适当减小胎圈内直径,适当增大胎圈与轮辋过盈量、三角胶尺寸、胎体反包高度,提高耐磨胶的硬度和耐老化性能,在推荐充气压力和负荷范围内使用轮胎及在车辆上安装液压减速器以降低刹车片使用频次等措施,可降低趾口空发生率,延长轮胎使用寿命。

矿用重载轮胎接地印痕的研究

以14.00R25宽体自卸车轮胎为例,通过轮胎使用情况调研,结合实验室测试和轮胎有限元仿真,研究矿用重载轮胎接地印痕及接地压力分布。结果表明:宽体自卸车轮胎接地印痕形状应接近矩形且接地压力分布均匀;影响轮胎接地印痕及接地压力分布的主要因素为断面高宽比、胎冠弧半径和弧度高、带束层角度和宽度、花纹沟壁角度和花纹沟宽度等。通过有限元仿真优化设计可避免轮胎出现花纹掉块和非均匀磨损等问题,提高设计效率。

降低6061铝合金宽幅加筋板型材平面度的工艺研究

研究了高温在线整形工装和仿形拉伸工装对6061铝合金挤压宽幅加筋板型材平面度的影响。结果表明,通过高温在线整形和采用仿形拉伸垫块进行拉伸矫直,可有效降低6061铝合金挤压宽幅加筋板型材的平面度。相比之下,高温在线整形对降低宽幅加筋板型材平面度的的效果比采用仿形拉伸垫块更明显。高温在线整形是利用铝合金在高温状态下硬度低、易矫直的特点,通过施加外力的方式对高温状态下的型材进行在线整形,使宽幅加筋板型材获得良好的平面度,同时配合使用仿形拉伸垫块进行拉伸矫直,生产的6061铝合金挤压宽幅加筋板型材可满足客户对平面度的要求。

超宽箱梁多桁片组合挂篮施工技术研究

该施工技术采用前上横梁、后上横梁将4片三角式主桁架主纵梁连接成整体形成多桁片组合挂篮。组合式挂篮的多片纵梁能有效地分配悬浇混凝土荷载,能避免由于梁段过重导致的主纵梁局部失稳现象,降低已浇节段混凝土的拉压应力(锚点抗拉反力和中支点承压力)。且梁段浇筑时,底模平台的底纵梁共同受力,协调变形,能有效防止挂篮前面发生扭转失稳,提高整体横向稳定性。多桁片组合挂篮总重约177 t,占最大节段重量的39.3%,具有自重轻,刚度大、变形小,结构简单,受力明确等特点,能有效解决超宽截面梁段在挂篮悬臂施工时的应力分布和挠度变形问题。由于使用通用设备,具有较好的参考意义。

基于分类处理-分质利用的电子电镀废水中金属离子资源化处理新技术研究进展

随着城市化、工业化以及农业现代化进程加快,电子信息行业快速发展的同时产生了大量电子电镀重金属废水。这类型废水成分复杂、赋存稳定、危害极大且具有一定资源属性,目前较流行的混凝沉淀法处理效果不佳,污泥量大,存在二次污染且无法资源化回收。基于此,归纳总结了电子电镀重金属废水的来源与危害,归纳分析了现行主要技术存在的不足,系统介绍了基于分类处理-分质利用的电子电镀废水中金属离子资源化处理的进展与最新研究成果,为电子信息行业清洁生产、重金属废水污染防治和资源化处理提供借鉴与技术支撑。